While designing listening tasks, it is very important to grade the difficulty level of the tasks.

Which of the following is true about the US Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

Which of the following is true about the U. S. Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

Which of the following is true about the U. S. Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

Which of the following is true about the U.S. Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

Which of the following is true about the U.S. Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

Which of the following is true about the U.S. Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

Which of the following is true about the U.S. Navy underwater listening network?

A．It is now partly accessible to civilian scientists.

B．It has been replaced by a more advanced system.

C．It became useless to the military after the cold war.

D．It is indispensable in protecting endangered species.

PART C

Directions: You will hear three dialogues or monologues. Before listening to each one, you will have 5 seconds to read each of the questions which accompany it. While listening, answer each question by choosing A, B, C or D. After listening, you will have 10 seconds to check your answer to each question. You will hear each piece ONLY ONCE.

听力原文： What is cloning? Cloning is the creation of cells or whole animals using DNA from a single "parent", by passing the normal reproductive process. The clone has the same DNA as the parent.

The most common process takes DNA from one cell and puts it in a hollowed-out egg. Chemicals and electricity are then used to encourage the new DNA to fuse with the egg and develop into an embryo. This technique is called nuclear transfer.

The first cloned animal in human history is a sheep called Doily. It is very important because it was the first mammal to be cloned using DNA taken from an adult cell. Previously, animals had only been cloned using embryo cells, which already have the potential to become a complete embryo in its own right. The big breakthrough with Doily was to make a clone from an ordinary, adult cell.

When it comes to the question of whether cloned animals are normal and healthy, the answer is YES. Dolly is, but scientists do not yet know whether this is the exception or the rule. Some early evidence suggests that clones may have health problems and that they may age prematurely.

With the birth of Dolly; many people are worried that a human clone may be born soon. It's possible in theory. But the technology of reproductive cloning is still in its very early stages and there is much that scientist do not understand. That's more, human cloning is already banned by law in the United Kingdom. The former President of the United States Bill Clinton proposed banning research into producing human clones in the US for five years. Some measures have also been taken to establish international agreements banning live human clones.

What has cloning bypassed?

A．The nuclear transfer

B．The process taking DNA

C．The normal reproductive process

D．The creation of cells

PART C

Directions: You will hear three dialogues or monologues. Before listening to each one, you will have 5 seconds to read each of the questions which accompany it. While listening, answer each question by choosing A, B, C or D. After listening, you will have 10 seconds to check your answer to each question. You will hear each piece ONLY ONCE.

听力原文： In the United States, those people who want to become doctors must attend four years of college or university. They usually study biology, chemistry and other sciences. There are 125 medical colleges in the United States, but it is difficult to gain entrance m them. In 2001, about 35 000 students applied to medical schools in the United States, but only about 17 000 were accepted. A medical education is also very costly and it costs as much as 30 000 dollars for each year.

After entering medical school, students spend the next four years studying only medical sciences. The first two years of medical school are spent mainly in class. The students learn about the body and all its systems. They learn about chemistry and medicines. And they begin studying diseases and how to recognize and treat them. Many students say the first year of medical school is the most difficult. They must remember a great deal of information for example, many schools require that students remember the names of every bone in the body.

By the third year of medical school, students are ready to use their knowledge to begin helping sick people in a hospital. These students work trader the guidance of experienced doctors. Students observe the treatment of patients. They also examine patients and advise treatment. As the students watch and learn, they think about the kind of medicine they would like to practice when they become doctors.

During the fourth year of medical school, students begin seeking to enter a medical training program in a hospital. This training program is called a medical residency. Medical school graduates face strong competition to gain a resident position at the hospitals they want most. Hospitals want the top medical school graduates.

The entrance rate of medical schools of the US in 2001 was ______.

A．near 20%.

B．30%.

C．near 50%.

D．80%.